I. Field of the Invention
This invention relates to a method of solidification or encapsulation of aqueous-containing compositions. The compositions can be any containing a continuous aqueous phase such as slurries of ion exchange resins, cements, clays, pigments and other dissolved or suspended materials. These aqueous-containing compositions can be completely solidified by the present invention for effective disposal. The invention also has utility in encapsulating biologically-active and chemically-active materials for controlled release of same. The invention has further utility as a drying agent for aqueous-based coatings and adhesives.
II. Relevant Art
Processes for solidifying wastes are known in the art. U.S. Pat. No. 4,077,901 discloses a method for encapsulating liquid or finely-divided solid waste by uniformly dispersing the waste in a liquid thermosettable polymer composition and thereafter curing the waste/polymer under thermal and catalytic conditions. U.S. Pat. No. 4,119,560 discloses a method of treating radioactive waste by introducing the waste solution in a hot, inert, liquid carrier, flashing off the volatile solvents, and coalescing the solid waste particles with a polymeric binder which cures at ambient or elevated temperatures. U.S. Pat. No. 4,382,026 describes a process for encapsulating radioactive organic liquids by contact with insoluble, swellable polymer particles and subsequently a curable liquid resin which is cured to a solid state. U.S. Pat. No. 4,530,723 teaches a method of encapsulation of ion exchange resins by mixing with 1) boric acid or nitrate or sulfate salts, 2) a fouling agent and basic accelerator, and 3) cement. Further, U.S. Pat. No. 4,530,783 describes solidification of radioactive wastes using a composition comprising unsaturated polyesters. All of the above methods are greatly limited in the amount of liquid material which can be solidified or encapsulated by a given amount of solidifier or encapsulant (i.e. typically in the range of about 1:1 to about 2:1 parts by weight liquid material to solidifier or encapsulant).
U.S. Pat. Nos. 4,427,836 and 4,468,498 disclose core-sheath polymers which are swellable by bases and useful as opacifying or thickening agents in water-based coating compositions. Applicants have surprisingly discovered that polymer particles similar to those described in the U.S. Pat. No. '836 and U.S. Pat. No. '498 patents can be used to solidify aqueous-containing compositions, such as waste products, and to encapsulate biologically-active or chemically-active materials for controlled release.